Back throw

A back throw (後投げ, Rear/back throw; commonly abbreviated as b-throw or Bthrow, and referred to as ThrowB internally) is a throw performed by tilting the control stick opposite to the direction the character is facing after having grabbed the opponent.

Back throws rarely lead to combos, but typically have good knockback (often more than forward throws) and thus can be used to set up edgeguards or KO opponents near the edges of stages. In Smash 64, all back throws have very high knockback and are viable KO moves, a trait that carries over to many back throws in future games.

Back throws with hitboxes consist of two or more hits on the grabbed opponent (the hitbox, then the throw), and can affect other opponents near the thrower. Additionally, some back throws may possess a collateral hitbox, which affects nearby opponents but not the victim of the throw. Unless stated otherwise, all back throws have the attacker put the opponent behind themselves in some way.

Fox, Falco, and Mii Gunner's back throws are the only ones to release projectiles, in the form of lasers that can be reflected and absorbed. Fox fires three lasers that cause no knockback, much like those of his neutral special; likewise, Falco in Melee and Brawl fires three lasers that cause weak knockback. In Smash 4 and Ultimate, Falco and Mii Gunner instead fire a single laser that deals much more knockback, with Falco's being capable of KOing near the edge at high percentages.

Kirby's back throw in Melee causes him to functionally leave the ground, and can be used for a Kirbycide. However, it is one of the only two standard throws in the series that can be escaped without receiving external knockback (the other being his forward throw). From Brawl onward, this is no longer the case.

Corrin's back throw possesses a tipper hitbox that only affects nearby opponents, and can KO considerably earlier than the throw itself. This is also the case for his forward throw.

Ness's back throw in all games except Smash 64 is the opposite of his forward throw, possessing very low base knockback, but very high knockback scaling, making it noticeably powerful at high percentages compared to other back throws. It is the strongest back throw in Melee, Brawl, and Smash 4, and one of the strongest throws overall, KOing under 140% from the center of Final Destination.

Villager's back throw in Smash 4, as well as Isabelle's in Ultimate, have similar properties, although they are slightly weaker.

Mario, Luigi, and Dr. Mario's back throws are among the strongest in all of their appearances. Mario and Dr. Mario's are at their strongest in Melee, while Luigi's is at its strongest in Brawl, all KOing under 110% near the edge.

Incineroar's back throw in Ultimate is the strongest in the game at the edge, KOing under 100%, which slightly outpowers even Ness's back throw.

In Melee, Mewtwo's back throw is very powerful, and is considered one of its best finishers, KOing at around 100% near the edge.

Charizard's back throw has almost no ending lag (only 4 frames in Brawl and Smash 4, and 7 frames in Ultimate), allowing it to combo into aerial attacks from low to mid percentages, especially in the latter two games due to the changes to hitstun canceling. If the opponent's air dodge or jump is successfully read, it can even lead into an aerial Flare Blitz and KO at low percentages near the edge.